Method of producing slots



Patented I Apr. 7, 1931 iUNITED STATES PATENT OFFICE.

CLARENCE COBERLY, OF LOS AN GELES, CALIFORNIA, ASSIGNOR TO KOBE, INC., LOS

ANGELES, CALIFORNIA, A CORPORATION F CALIFORNIA METHOD 0F PRODUCING SLOTS Application filed January This invention relates to a method of and v apparatus for producing slots in metal, having hardened walls, this method and apparatus being very valuable inthe production of screen casings for wells.

My invention is of a character which renders it capable of producing a variety of types of slots having hardened surfaces. It

is advantageous in the various arts where Walls of slots are subjected to wear to .have their faces or walls hardened so that they will resist wear and not be rapidly enlarged to a greater size. One example of the utility of a slot of this character is found in the oil industry.. When a well has been drilled and the oil bearing strata reached, a well casing is lowered therein for supporting the` wall of the well and for excluding ground water. At the lower end of the well casing, there is attached a screen casing or strainer comprising casing having comparatively narrow slots provided therein. The oil and very small particles of sand contained therein flow through the slotsinto the casing, the larger particles being excluded by these slots.

The small abrasive particles of sand passing through these slots tend to wear away the surfaces and enlarge them, thus allowing lar er particles to enter the well casing, which they will gradually clog up. It is desirable that the walls ofthese slots resist wear so that they will retain their proper size and prevent entrance of larger destructive particles of sand or gravel.

It is an object of this invention to provide a method of producing slots in metal, these slots having hardened walls.

It is another object of the invention to provide a method for producing slots in a metal and hardening the walls thereof simultaneously. My invention comprises heating ran area of metal, cutting a slot in the heated area and hardening the heated area of metal around the slot. It is preferable to heat and cut the metal by use of a cutting torch having a preheating flame which preheats the metal and having a metal removing stream of oxygen which produces the slot. There are various means which I may employ for hardening the walls ofthe slots and the area adj a- 5, 1925. Serial No. 737.

cent thereto. I may rapidly cool the heated walls of the slot by rapidly drawing cool air through the slots while themetal therearound is still hot, thus chilling and hardening the walls of the slot. Another method of hardenl ing is by adjusting the heating flame of the cutting torch to have an excess of carbonizing material. This supplies carbon to the heated walls. The walls are then rapidly cooled as before, thus eiiicently hardening the previously carbonized area. Another means of hardening the "walls of the slots is by providing an extra supply of carbonizing material as acetylene, ethylene and cyanogen. Such material, carbonizing the heated walls, has a case hardening effect. I may also accomplish the hardening of the walls of the slots by supplying a concentrated solution of liquid hardening agent such as potassium cyanide to the heated walls, this solution giving up carbon and producing case hardening.. A slot having the walls thereof hardened in this manner offers a great resistance to wear and functions effectively for a much longer period of time than the usual walls of slots which are not hardened.

It is another object of the invention to provide an apparatus for carrying out the above stated method.

It is a still further object of the invention to provide a method of and apparatus for producing screen casing.

Other objects 'and the specific advantages of my invention will appear in the following description.

Referring to the drawing inV which I show my invention adapted to produce screen casing, this particular adaptation being shown s0lely for illustrative purposes,

Fig. 1 is an essentially diagrammatic `View illustrating a form of apparatus adapted to carry out my invention. l

Fig. 2 is an enlarged section taken through a slot showing the case hardened area therearound. y

As shown in Fig. 1 of the drawing, a metal member which is to haveslots provided therein is shown in the form of a pipe or casing 11. Inside the casing 11 I provide a pair of heads 12 and 13 which are connected together 100 by rods 14. These heads 12 and 13 are arranged to provide a closed chamber 15 inside the casing 11 and between the heads 12 and 13. Extending from the head 13 is a suction ipe 16 which communicates through the head 13 with the chamber 15. rlhe pipe 16 is connected with a slag box 18, this slag box 18 having an exhaust pump 19 connected therewith by a pipe 20. The exhaust pump 19 is driven by a suit-able motor 21 and is for the purpose of creating a vacuum or suction in the slag box 18. rlhis draws air from the chamber 15 through the pipe 16 creating a vacuum in the chamber 15.

After the apparatus, just described, has been installed, a slot (as indicated at 24) is cut in the wall of the casing 11 enclosing the chamber 15. The slot 24.is cut by means of a cutting torch 25 which is of a standard design. The torch 25 is first positioned, as indicated by the dotted lines 27, directly over a small hole indicated at 28 which has been drilled through the Wall ofthe casing 11 to start the cut. When the heating iame has heated the area around the hole 28 to the desired temperature, a stream of oxygen is also sent out vof the torch 25, and the torch is moved along the pipe producing the slot 24. During the formation of the slot 24, air is drawn through the slot and the heated walls thereof are rapidly cooled. This rapid cooling serves to chill and harden the walls of the slot. The slag formed by the cutting of the slot 24 is drawn with the air through the pipe 16 to the slag box 18 where it collect-s and may be disposed of at intervals.

As previously mentioned, the heating ame of the torch 25 may be adjusted so as to possess an excess of carbonizing material. Cutting torches in common use generally use acetylene and oxygen as a fuel. In this case, the .flame would be adjusted soas to have an excess of acetylene. As the metal is heated and the slot is cut, the excess of acetylene in the heating fiame carbonizes the heated metal around the slot 24 and this metal when rapidly cooled is very hard. It will be seen that this method produces a case hardening effect on the walls of the slot 24.

If desired, I may provide a carbonizing material head 29 which may be employed in conjunction with the torch 25. As the torch 25 is drawn along the casing 11 heating the metal and cutting the slot, a carbonizing material may be supplied to the walls of the slot by the head 29, thus carburizing these walls. A case hardening effect is thereby obtained when the walls are cooled. I may Vsupply any well/known case hardening or carburizing material through .the head 29 such as acetylene, ethylene and cyanogen, or any other hydrocarbon gas. Any of these gases supply carbon to the heated area around the slot which carburizes and case hardens the surfaces when they are cooled.

iut/saaie Instead of supplying any of these hydrocarbon gases, l may supply through the head 29 a liquid hydrocarbon, or any well known carburizing liquid such as a solution of potassium cyanide. rThe liquid as it contacts and outer faces 33 and 34 of the casing 11 75 are hardened around the slot 24 as well as lthe walls of the slot. The hardening of the walls of the slot and the area adjacent tothe slot provides a slot which will withstand considerable frictional wear and will have a long life owing to the fact that the abrasive articles carried in the oil will have little e ect thereon.

1 claim as my invention:

1. A method of producing a slot having @5 hardened walls in a metal plate comprising: applying heat to a limited area of said plate; passing an oxidizing jet through said plate within said heated area; moving said jet to produce a slot; and hardening the walls of said slot by drawing air therethrough while the walls of said slot are heated to a high temperature.

2. A method of providing a hardened slot in oil well casing which comprises: heating a limited area of said casing; passing an oxidizing jet through said casing within said area; causing a relative movement between said jet and said casing in such a manner as to form said slot; and establishing a partialvacuum within said casing for` the purpose of causing a iow of air through said slot in contact with the highly heated walls of the slot.

3. A method of Providing a hardened slot 195 in oil well casing which comprises: heating a limited area of said casi-ng; passing an oxidizing jet through said casing within said area; causing a relative movement between said jet and said casing in such a manner as to form said slot; supplying a hardening material to the highly heated walls of said slot; and establishing a partial vacuum within said lcasing for' the purpose of causing a How of air through said slot in contact with the highly heated walls of the slot.

4. A method of forming slots having hardened walls in a sheet of metal which consists in establishing a dierence in fluid pressure on opposite sides of said sheet, and cutting er pressure side to the lower pressure side of said sheet.

5. A method of forming slots having hardened walls in a pipe which consists in establishing a diference in uid pressure between the interior and exterior of said pipe and meaere cutting slots in said pipe with a torch, the Walls of said slots being heated by said torch and cooled by the passage of said Huid through said slots as soon as it is formed from the higher pressure side to the lower pressure side of said pipe.

In testimony whereof, have hereunto set my hand at Los Angeles, California, this 30th day of December, 1924.

CLARENCE J. COBERLY, 

